THURSDAY, Sept. 7, 2017 (HealthDay News) — Poor olfaction is associated with increased risk of incident Parkinson’s disease (PD), according to a study published online Sept. 6 in Neurology.
Honglei Chen, M.D., Ph.D., from the National Institute of Environmental Health Sciences in Research Triangle Park, North Carolina, and colleagues examined olfaction in relation to incident PD among 1,510 white and 952 black participants of the Health, Aging, and Body Composition study. Olfaction of study participants was assessed with the Brief Smell Identification Test (BSIT) in 1999 to 2000.
The researchers identified a total of 42 incident PD cases, including 30 white and 12 black participants, during an average of 9.8 years of follow-up. Poor sense of smell (indicated by lower BSIT score) correlated with increased risk of PD. The hazard ratio was 1.3 (95 percent confidence interval, 0.5 to 3.6) and 4.8 (95 percent confidence interval, 2 to 11.2) for the second (t2) and lowest (t1) compared with the highest tertile (t3) of BSIT (P trend < 0.00001). In the first five years of follow-up and thereafter, there were significant associations for incident PD (hazard ratios t1/[t2+t3]), 4.2 [95 percent confidence interval, 1.7 to 10.8] and 4.1 [95 percent confidence interval, 1.7 to 9.8]). The association was stronger in white than black participants and for men versus women.
“Poor olfaction predicts PD in short and intermediate terms; the possibility of stronger associations among men and white participants warrants further investigation,” the authors write.
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